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75ea58593b
Consider the following (Ada) variable...
A1 : Array_Type := (1 => (I => 0, S => <>),
2 => (I => 1, S => "A"),
3 => (I => 2, S => "AB"));
... where Array_Type is an array of records whose size is variable:
subtype Small_Type is Integer range 0 .. 10;
type Record_Type (I : Small_Type := 0) is record
S : String (1 .. I);
end record;
type Array_Type is array (Integer range <>) of Record_Type;
Trying to print the value of this array currently results in the following
error:
(gdb) p a1
Cannot access memory at address 0x61c000
What happens in this case, is that the compiler describes our array
as an array with a specific stride (and bounds being static 1..3):
<1><749>: Abbrev Number: 10 (DW_TAG_array_type)
<74a> DW_AT_name : (indirect string, offset: 0xb6d): pck__T18s
<74e> DW_AT_byte_stride : 16
<74f> DW_AT_type : <0x6ea>
<2><757>: Abbrev Number: 11 (DW_TAG_subrange_type)
<758> DW_AT_type : <0x75e>
<75c> DW_AT_upper_bound : 3
This is because we cannot use, in this case, the size of the record
to determine that stride, since the size of the record depends on
its contents. So the compiler helps us by providing that stride.
The problems start when trying to resolve that type. Because the elements
contained in that array type are dynamic, the array itself is considered
dynamic, and thus we end up creating a resolved version of that array.
And during that resolution, we were not handling the case where the array
had a stride. See gdbtypes.c::resolve_dynamic_array...
return create_array_type (copy_type (type),
elt_type,
range_type);
As a result, we created an array whose stride was based on the size
of elt_type, which a record whose size isn't static and irrelevant
regardless.
This patch fixes is by calling create_array_type_with_stride instead.
As it happens, there is another issue for us to be able to print
the value of our array, but those are independent of this patch
and will be handled separately. For now, the patch allows us to
get rid of the first error, and the output is now:
(gdb) p a1
$1 = (
gdb/ChangeLog:
* gdbtypes.c (resolve_dynamic_array): Use
create_array_type_with_stride instead of create_array_type.
README for GNU development tools This directory contains various GNU compilers, assemblers, linkers, debuggers, etc., plus their support routines, definitions, and documentation. If you are receiving this as part of a GDB release, see the file gdb/README. If with a binutils release, see binutils/README; if with a libg++ release, see libg++/README, etc. That'll give you info about this package -- supported targets, how to use it, how to report bugs, etc. It is now possible to automatically configure and build a variety of tools with one command. To build all of the tools contained herein, run the ``configure'' script here, e.g.: ./configure make To install them (by default in /usr/local/bin, /usr/local/lib, etc), then do: make install (If the configure script can't determine your type of computer, give it the name as an argument, for instance ``./configure sun4''. You can use the script ``config.sub'' to test whether a name is recognized; if it is, config.sub translates it to a triplet specifying CPU, vendor, and OS.) If you have more than one compiler on your system, it is often best to explicitly set CC in the environment before running configure, and to also set CC when running make. For example (assuming sh/bash/ksh): CC=gcc ./configure make A similar example using csh: setenv CC gcc ./configure make Much of the code and documentation enclosed is copyright by the Free Software Foundation, Inc. See the file COPYING or COPYING.LIB in the various directories, for a description of the GNU General Public License terms under which you can copy the files. REPORTING BUGS: Again, see gdb/README, binutils/README, etc., for info on where and how to report problems.